The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Mechanical clutches such as dog clutches are common components in diverse mechanical power transmission devices. Whereas friction clutches are utilized in applications requiring the ability to synchronize and couple two rotating elements often having an initial speed differential, dog clutches are utilized in applications where there is generally little or no speed differential prior to engagement. Generally speaking, dog clutches comprehend a first rotating element having uniformly, circularly spaced projections and a second, co-axial element having complementarily disposed recesses. The projections and recesses may be so sized and arranged that the two elements are identical. Additionally, certain edges of the projections and recesses may be oblique such that the transmitted torque tends to achieve and maintain full engagement of the clutch elements.
Like many engineering compromises, the incorporation of oblique edges on the projections and recesses, while minimizing the possibility of spontaneous disengagement during power transmission, may also make the clutch difficult to intentionally disengage under load. In fact, even dog clutches with engaging edges that are flat, i.e., parallel to radial planes, may be difficult to disengage if they are carrying relatively significant torque loads unless and until the torque load across the projections and recesses is reduced or terminated.
Thus, while dog clutches provide a simple selectable connection between power transmission components which may require little or no external agency to maintain engagement, the difficulty of disengagement under load requires either that the clutch operator be extraordinarily robust or that load be reduced or removed from the clutch before it is disengaged. The present invention offers a third option.